Datastore limits

[Mr_Ball]

Hi,

I just installed ESXi 4.1.0, 260247 on a Dell PowerEdge R710, with a 15x1TB PowerVault MD1000 in a RAID 50 (1 dedicated hotspare), using the Perc 6/E controller.

But, when i try to partition the RAID50 volume, i get a max of 1,9TB disk, and i cannot expand it further.

As i can see there is a limit of the VMDK files of 2TB, and then I would think that it should be possible to have a datastore larger than 2TB?

The disk in the device list is 10,91TB, but as written above, im not able to create a VMFS partition with 10,91TB, only 1,9TB.

I did find this on wikipedia:

Can support LUNs with max size of 2TB and a max VMFS size of 64 TB as of version 4 (vSphere).

http://en.wikipedia.org/wiki/VMware_VMFS

Does that mean i have to split my RAID50 into small VirtualDisks in the RAID controller, or am i reading it in the wrong way?

If so, how would be the correct way to do so?

Any suggestions is welcome..

Best regards,

[mwpreston]

The Max size of a datastore is 2TB or 1.9TB or whatever with your block size.

The only way to get a larger datastore is to the extend feature, which basically glues the datastores together.

It's all outlined in this KB

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1752

[a_p_]

Currently ESX(i) is limited by the SCSI-2 protocol limits (see http://kb.vmware.com/kb/3371739)

When you present a LUN larger than 2 TB minus 512 Bytes, you will only be able to create a datastore with approximately the LUN size modulo 2TB.

To use all of the 10.9 TB you will have to present the disk space as several smaller LUNs. Even though you are able to use extents on the ESX(i) hosts to create datastores with up to 64TB (using 32 extents) I would not recommend to do so. The maximum virtual disk size is also limited to 2TB minus 512 Bytes.

André

[DSTAVERT]

Yes you would need to split your LUNs into 2TB - 512 byte virtual disks in the array configuration interface. It is possible to create larger datastores by using extents to "glue" them together but It isn't a good thing to do. Stick with the 2TB or smaller LUNS (virtual disks)

[Mr_Ball]

Hmm, i can't understand why the VirtualDisk cannot be partitioned out i n of partitions/datastores.

If i choose to create 5 raid 5 on the 15 disks, i'm i will loose the functionality of raid 50 or 60 (the data will not be spread out on all disks and only a few disks/performance?).

Any suggestions how to create the RAID?

Best regards,

[Josh26]

Mr_Ball wrote:

Any suggestions how to create the RAID?

Best regards,

Hi,

Any decent RAID card will allow you to create one RAID5 disk and present it as 5x logical disks, for five different datastores.

[DSTAVERT]

Check your PERC documantation. You need to create Virtual Disks on the array controller. Each virtual disk can be spread across any RAID configuration and number of drives you have available.

[a_p_]

The PERC 6/E supports all kind of RAID levels (0,1,5,6,10,50,60). However, RAID levels 10, 50 and 60 don't support to split the RAID into multiple logical volumes. What you can do is to create a large RAID 6 using all disks and then create the logical volumes from this RAID set. According to DELL's manual a RAID 6 should be preferred over a RAID 5 + hot spare if only one RAID set is created.

see http://support.dell.com/support/edocs/storage/RAID/PERC6/en/PDF/en_ug.pdf

André